When deploying wireless communication networks, there is a balance between coverage and capacity. On the one hand, a few large cells can provide great coverage but at a cost of reduced capacity. On the other hand, a scenario with many small cells creates better capacity and throughput, but may not provide the desired coverage. Hence, there is often a combination of larger cells to provide sufficient coverage with smaller cells to provide better capacity.
However, providing coverage indoors using many small cells can be quite costly, with a radio base station for each such small cell. Moreover, when the cells get too small, wireless terminals moving in the network cause a great number of handovers which causes significant overhead.
One solution to this problem is to use remote radio heads, where several remote radio heads connected to the same radio base station share the same cell. In this way, a single radio base station can provide coverage in different parts of a building by placing the remote radio heads appropriately. Moreover, the wireless terminal can move between the coverage of different remote radio heads while staying within the same cell, thus avoiding causing handovers.
However, when analogue signals are used for the transmission of signals between the radio base station and the remote radio head, there is a significant risk of noise and/or interference, which can have significant effects on performance.